/* 设置start样式*/
.start{
	position: absolute;
	/*top: 35%;
	left: 45%;*/
	top: 50%;
	left: 50%;
	margin-top: -90px;
	margin-left: -75px;
	transform: ;
}
.start:hover .startb{
	opacity: 0;
	transition: 1s;
}